An Eco-Friendly Antifouling Coating Based on Tannic Acid

Marine fouling has caused serious economic losses, and exploring multiple eco-friendly antifouling strategies has a positive significance. As a natural polyphenolic antioxidant, Tannic acid (TA) has a wide range of sources and biosafety, excellent antibacterial properties and its special chemical structure makes it easy to bind to the surface, which may provide inspiration for the development of antifouling materials. In this paper, a TA-based antifouling coating was designed and prepared. A stable intermediate transition layer was formed by co-deposited 3,4-dihydroxy phenyl-L-alanine (DOPA) and polyethyleneimine (PEI) on the surface of polyvinyl chloride (PVC), and then TA molecules were grafted on that surface to prepare a TA functionalized (PVC/(PDA/PEI)-TA) coating. The effect of the coating on the adhesion of marine bacteria and benthic diatoms was investigated. Then, the effect of TA on the adhesion behavior of mussels on the coating surface was studied. The results indicated that the coating had good antifouling performance. Marine bacteria and benthic diatoms had a low adhesion rate on the coating surface and were prone to the detachment under water flow erosion. The TA on the coating surface affected the adhesion behavior of mussels. Mussels did not like TA coating and only secreted a small amount of adhesive plaques on the surface. Moreover, the adhesion force between the plaques and the substrate was low. This study may provide new solutions to marine biofouling.